Method for producing lubricating oil



Oct. 22, 1940. u, B.A BRAY l METHOD FOR PRODUGING LUBRICATING OIL FiledOct. 6, 1950 2 Sheets-Sheet l Wild mw U. B. BRAY 2,218,516

METHOD FOR PRODUCING LUBRICATING OIL Filed oct. e, 195o 2 sheets-sheet 2Oct. 2.2, 1940.

Patented oa. 22, 1940 PATENT OFFICE METHOD FOR PROlIIJEING LUBRICATINGUlric B. Bray, Palos Verdes Estates, Calif., as-

signor to Union Oil Company of California, Los Angeles, Calif., acorporation of lCalifornia.

Application October 6, 1930, Serial No. 486,724 y claims.

sion of Serial No. 466189l claiming dewaxing4 with butane with orwithout heating of the waxbearing oil with butane to effect solutionprior to chilling; Patent No. 1,944,491, claiming separation of asphaltand wax from oils containing them; Patent No. 1,949,989, ,claimingseparation of asphalt from oils by treatment with liquefied normallygaseous hydrocarbon with or Without washing of precipitated asphalt withfresh solvent; Patent No. 2,006,098,` claiming chemical treatment ofoilsdissolved in a liquefied normally gaseous hlydrocarbon solvent;Patent No. 2,031,204,r claiming deasphalting and/or dewaxing with aliquefied volatile solvent and with a heavier solvent material; andPatent No. 2,081,731, claiming distillation of oils to remove lightfractions, substantial deasphalting of the residue, andthe subsequentdistillation of the partially deasphalted residue to produce alubricating oil distillate.

It has been discovered that superior lubricating oils and asphalts canbe obtained from 4crude oil by causing separation of the lubricatingoilfrom the asphalt at temperatures below that at which deleterious changesare induced in the oil.

It has been found that if oil containing asphalt is heated in thepresence of the asphalt, the latter catalyzes certain reactions in theoil which .result in the destruction of those characteristics of e thelubricating oils which are most desirable.

It has been found advisable to cause the sepaf ration of asphalt fromthe oil by means of volatile solvents which are capable of dissolvingthe oil and any Wax and which do not dissolve the asphalt. Such solventsare light petroleum fractions, such as casinghead gasoline and naphthaand also petroleum fractions normally vaporous at ordinary temperaturesand pressures. Other solvents which may be used are alcohol, ether,mixtures of alcohol and ether,acetone, etc. I prefer to use as myvolatile solvent a petroleum fraction obtained by the rectiflcation'ofnatural gasoline. The fractions are composed in the main of propane andisobutane. A typical analysis of such a fraction is l6.72% ethane, 72.2%propane and 19.91%-isobutane and 1.17% normal butane. It will beunderstood, however, that these merely illustrate the type of fractionused and the composition may vary. This fraction will hereinafter bereferred to as propane for purposes of simplicity. A

In order to cause the extraction with this liquid lo fraction, thesolution is maintained at a pressure suicient to maintain the propaneliquid at ordinary temperatures. The fraction above described is liquidat ordinary temperatures at about lbs. The extraction of the oil fromthe asphalt at such pressures results in an asphalt substantially freeof oiland a solution of oil in the liquid petroleum fraction. Thissolution contains substantially all the wax present in the crude oil.

It has also been4 found that oil containing asphalt and impurities suchas Vwax may be first -freed from the asphalt by a primary extractionwith a light solvent such as the solvent described above and that theimpurities such as wax may then be removed at a suitable temperature bythe aid of a heavier solvent such as naphtha in4 which the wax issubstantially insoluble at the lowl temperature employed. By heaviersolvent I mean one of higher boiling point than the light solventpreviously described.

Advantage is taken of the high volatility of the light solvent to causea cooling of the oil upon a release of pressure to produce theseparation of the contained Wax. A further advantage in cooling the oilin this manner is to bring the oil to a proper temperature for acidtreatment. By acid treatment I intend to include treatment with acidfollowed by the step of neutralization and/or clay treatment.

If a large proportion of the propane is removed from the solution afterthe asphalt has been separated, the remaining solution becomes tooviscous and not of sufficiently low specic gravity to permitsatisfactory behavior in the dewaxing operation which is convenientlyaccomplished in a centrifuge. Dlmculties are also encountered inchemically treating oils oi' high viscosity.` My invention avoids thesediiiiculties by mixing the oil with naphtha before dewaxing to reducethe vis- 4cosity and place the oil in proper Condition f01 50 dewaxing.'I'he reduced viscosity is also advantageous in chemical treatment ofthe oil. If naphtha is expanded at very low pressure into the oil priorto dewaxing, it may also have a cooling effect similar to that caused bythe expansion of 55 ethylene, trichlorethylene or the like, or mixturesof benzol with acetone or other ketones, or mixtures of benzol andbutanol or other alcohols.

In addition to the power which thenaphtha has of reducing' the-viscosityof the asphalt-free oil, it also is used as an extracting medium for waxor other material whose presence is deleterious in a finished, highgrade lubricating oil. The naphtha 'if used in sufficient quantitiesacts as a solvent for the oil during the removal of the wax or otherimpurities in a manner similar to the action of the propane solutionduring the removal of the asphalt. By regulating the quantitysubstantially oil free wax may be precipitated. In comparing theirvolatility and specific gravity, the propane is considered to be thelight solvent and the naphtha is the heavier solvent. An advantage inusing both light and heavy solvents resides in the fact that th'edewaxing may take place in the presence of the heavier solvent after thelighter, more volatile 'solvent has been evaporated with a consequentdecrease in the temperature of the wax containing oil. A y

It is therefore an object of'my invention to produce lubricating oilfrom oil containing aspurities such as wax from the asphalt free oil bymeans of a heavier solvent under reduced pressure. e

It is furthermore ,an object of my invention to produce lubricating oilfrom oil containing asphalt and wax by mixing this oil with a solvent inwhich the lubricating oil fractions and wax are soluble, but in whichthe asphalt is insoluble, and subsequently separating the wax from thelubricating oil fractions in the presence of naphtha. .Y

It is a further object of this invention to mix the naphtha with the oileither in the presence of substantially all the propane used toprecipitate the asphalt, or in the presence of only a portion of saidpropane, or the naphtha may be added after substantially all the`propane has been separated from the oil and wax.

It is a further object of this invention to produce lubricating oil fromoil containing asphalt and wax by precipitating the asphalt with a sol-,vent for the oil and wax and to chemically treat the oil either beforeor after removal of the Wax from the oil, and either before or after theaddition of naphtha to the oil and wax.

Another object of this invention is to produce lubricating oil from oilcontaining asphalt and wax by mixing a volatile solvent therewith underpressure to precipitate the asphalt and dissolve the lubricating oilfractions and wax, separate the precipitated wax under pressure, andtaking advantage of the highly volatile characteristics of the solventby releasing the pressure and allowing the solvent to vaporize andconsequently cool the oil and wax, lthereby precipitating the latter,and to separate the wax from the oil in the presence of naphtha.

Another object of the invention is to produce lubricating oil in themanner described above and to make further use of the volatility of thesolvent by partially releasing the pressure on the oil, solvent and waxsubsequent to the removal of` the precipitated asphalt under pressure,whereby the oil, wax and the solvent which remain in the liquid form aresuiciently cooled to be at the desired temperature for chemicaltreatment, and after chemical treatment, making use of the volatility ofthe remaining solvent byfurther releasing the pressure andprecipitatingthe wax due to the consequent cooling.

The process will be more adequately understood by reference to thedrawings which show preferred schematic arrangements of the apparatus tocarry out the process described herein.

Fig. 1 is a schematic arrangement of apparatus in which the oil is firstmade asphalt free and thenis dewaxed in the presence of naphtha andchemically treated in the substantial absence of solvent.

l Fig. 2 is a schematic arrangement of apparatus in which the oil isfirst made asphalt free and then is dewaxed in the presence of naphthaand chemically treated in the presence of substantial quantities ofsolvent.

Referring more particularly to Fig.. l, topped residuum obtained bydistilling crude oil at a temperature preferably not over 60G-625 F. toremove all fractions up to and including all or a portion of the lightlubricating oil, is taken from tank I and is passed through line 2 topump 3 and to T 4 where it meets a propane solution of lubricating oilcoming through line I5. 'Ihe propane and residuum pass through theturbulence or mixing coil 5 and then into decanter 6;

The asphalt in the'residuum is precipitated by the propane and settlesto the bottom of decanter 6 in the form of a. slurry which is passedthrough pump 'I and line I Il where it is mixed with propane fromstorage 8 via pump 9 and line I0. 'I'he mixture then is passed intomixing coil II and into decanter I2. lDecanters 6 and I2 and propanestorage 8 are maintained at the same pressure by means of equilibriumlines I6 controlled by valves I1. The pressures in 6, I2 and 8 aresufficient to maintain the solvent in liquid state at ordinarytemperatures. For"the solvent given above, this is about 125 lbs. persquare inch.

The clear overflow from decanter I2, consisting of liquid propane inwhich is dissolved a small amount of lubricating oil, is passed throughline I3, pump I4 to line I5 to T 4 where it is mixed with the incomingtopped residuum and passes through turbulence coil 5 into decanter 6, asdescribed above. 'I'he asphalt slurry from decanter I2 is'drawn offthrough the pressure release valve IB and ashed through coil I8 infurnace 20. Sucient heatis supplied to cause vaporization of the propaneand to melt the asphalt. The heated mixture of asphalt and propane isnow sent into evaporator 2| where superheated steam is introduced via 22in order to complete the evaporation of the propane and to reduce theasphalt to satisfactory iiash and fire speciilcations. The overhead fromevapo- IThe overflow from decanter 6, consisting of a.

more concentrated solution of lubricating oil and propane is passedthrough pump 35 and line 34 through pressure reduction valve 36 where itmeets naphtha from tank 31 passing through pump 38 and valve'39. In theoperation of cooling chamber 4|, if a very large portion of the propaneis evaporated, the remaining solution would be too viscous and not ofsufliciently low specific gravity to permit satisfactory behavior in thedewaxng operation. Therefore, a suitable quantity of naphtha is added inline 48 to the incoming propane solution. The addition of the naphthaalso reduces the loss of propane in the centrifuging operationif thecentrifuge is not gas tight in construction.

It is desired to release the pressure upon the propane solution so thatpropane will evaporate from the solution and thereby suiliciently lowerthe temperature of the remaining solution to permit asatisfactorydewaxing operation. The propane solution passing through pressurereductionl valve 36 goes through line 48 into cooling chamber 4| whichis in effect a rectifying column held at a predetermined pressurecorresponding to the desired 'dewaxing temperature. As the propaneevaporates the temperature of the remaining solution falls to that inwhich the vapor pressure will correspond to that being maintained in thecooling chamber by propane compressor 43. The

propane vapors pass out through line 42 to compressor 43. The conditionsin rectifying column 4| are maintained by the prooer manipulation ofvalve 36 and by controlling the suction of compressor 43 so that onlythe solvent is removed and the lubricating oil and naphtha are retainedas bottoms. By reducing the pressure to substantially atmospheric atemperature of 40 F. can be obtained. Substantially al1 the propane maybe removed from the solution in rectifying column 4| or only thenecessary quantity may be allowed .to vaporize therefrom in order toprovide for sufficient cooling to dewax the oil. If desired, the vaporsrising in the column 4| may be washed by the addition of naphtha intothe top thereof. 'I'he compressed vapors leaving compressor 43 passthrough line 32 to condenser 33 where the vapors are liquefied andpassed into liquid propane storage 8.

The cooled mixture from the bottom vof rectifying column 4| is carriedthrough line 44 to -pump 45 from which it is sent to centrifuge- 46. Thecentrifuge, is operated by motor 41 which is positioned outside a gastight insulated chamber 48 which contains centrifuge 46. Wax isdischarged from the centrifuge through line 49. The discharged wax maybe worked up in any suitable manner for the recovery of propane, naphthaand oil. The dewaxed'oil is discharged through line 58 and is passedinto heater 5|. The heater 5| may consist of any convenient equipmentwhich will impart heat to the cold oil passing through line 58, such asa heated coil set in a furnace or heat exchanger. As shown it is a steamheater, steam entering at 52 and leaving at 53. The dewaxed oil solutionleaving heater 5| may be sent by either of two courses.

If it is desired to acid and alkali treat the de- Waxed lubricating oilstock while in naphtha solution, the oil is lpassed through valve 54 toevaporator 55. In yevaporator 55 practically all of the remainingpropane is removed from the solution, passed through mist extractor 55',through line 56 to propane compressor 38, where it is compressed andsent through line 3| and line 32 to condenser 33 where it is liqueed andpassed into propane storage 8. The column 55 is operated to keep thenaphtha in the oil by the proper manipulation of valve 54 and bycontrolling the suction of propane compressor 38. This is merely asimple rectifying step. Rectifying plates may be provided to assist inthis operation as will be understood by those skilled in the art.

The naphtha solution from the bottom of evaporator 55 passes throughpump 58, line 51 to dewaxed naphtha solutionstorage 59. From 59 thedewaxed naphtha solution passes through valve 6|, pump 62, via line 88to agitator 63 Where itis treated with sulfuric acid from tank 64,pumped by 65 through valve 66 in line 61. The acid treated oil isdecanted from the sludge through the valves 1| and lines 184 and runinto agitator 13 through line 12. The acid sludge is withdrawn throughline 68 controlled by valve 69. In 13 it 1s rst treated with waterpassing from 18 via pump 19 and valve 88 through line 11. `lIhe water iswithdrawn through 8|` controlled by valve 82. The oil is then treatedwith caustic soda passing from 14 via pump 15 and valved line 16 to line11. 'I'he spent caustic is withdrawn through 8|. The alkali treated .oilis then washed with water as previously described. The treated naphthasolution is carried from agitator 13 by line 83. The treated naphthasolution passes through line 83, pump 84, line 85, valve 86 to heatinterchanger 81. y

If it is not desired to perform the acid and alkali treatment in thepresence of the naphtha, the oil leaving heater 5| is passed throughvalve 54' to heat interchanger 81, valves 54 and 86 being closed andvalve 54' open. Oil leaving 81, Where its temperature is raisedsomewhat. is sent through line 88 to coil 89 in furnace 28 wh'ere itstemperature is raised still further before being introduced intoevaporator 9| Athrough line 98. Steam is introduced via 92 in evaporator9| to aid in the flashing of the naphtha and residual propane and toreduce the remaining oil to satisfactory flash and fire specifications.`The oil remaining in the bottoml of evaporator 9| vis drawn of! throughline 93 and sent tov dewaxed oil storage 95 via pump 94. If the oil hasnot been chemically treated in naphtha solution, it may now be treatedfree from naphtha.

The treated naphtha solution travels from heat interchanger 81 in thesame path described above in order to be freed of naphtha and residualpropane.

The overhead from evaporator 9| is passed through 96 and, heat.exchanger 81 into line 91 and is further condensed in condenser 98 fromwhich it passes into separator 99. 'Ihe naphtha condensate is sent bypump |82 through line |83 to naphtha storage 31. Any uncondensed propanein separator 99 passes through line |88 to propane compressor 38. Thecompressed propane passes through line 3| and 32 to condenser 33 whereit liqu'ees and passes to propane storage 8. The condensed steam iswithdrawn through IOI.

Referring more particularly to Fig. 2, this embodiment `relates to theaforesaid process in which a modification is made whereby the chemicaltreatment takes place in the presence of substantial quantities of thesolvent which is in solution with the oil and wax.

The crude oil to be used as a source of lubricating oil is taken from acrude oil storage tank I and sent by pump 2 through coil 2 in furnace 3,whence it is.sent to evaporating column 4. The vapors passing throughline 5 consist of gas oil, kerosene and gasoline vapors which go todephlegmator 6 where they are fractionated into gasoline overhead andkerosene and gas oil bottoms. These may be rerun or handled in anyconventional manner. The vapors passing through 1 are condensed incondenser 8 and the condensate, i. e., gasoline, is collected in 9. A

' part thereof may be returned by pump I0 through line I controlled byvalve 9 to distributor I to act as a reflux. The dephlegmator bottomsare removed through by pump I2 and are cooled in I3. They consist of gasoil and kerosene. Part thereof is returned as a wash via line |4 andspray I5.

The bottoms from evaporator 4, consisting of fuel oil or refineryresiduum, pass through the run-down line I6 to the hot residuum storagetank |1 which may serve as a surge tank in the continuous operation ofthe process. The hot residuum from tank .I1 is passed through pump I8which sends the hot residuum through coil I9 in furnace 20 where theresiduum is heated to about 625 F. Care is taken at this point not tooverheat the residuumbecause of the danger of injuring the quality ofthelubricating oil to be obtained as the nal product. The heated residuumpasses to fractionating column 22.

Steam superheated in coil 2| is introduced in If desired, as many tanksas there are side streams A may be employed. The side stream distillatesmay be processed in any suitable manner to produce desirable products.

The overhead from column 22 is removed through line 29, cooled incondenser 30 and sent to receiver- 3I. Uncondensed vapors areremovedtherefrom via 32 while condensed oil and water from the steam used incolumn` 22 are removed via lines 33 and 34 respectively. The bottomsfrom column 22 are run through line 35 by pump 36 to heat exchanger 31and line 38 to cooler 39 from which they are delivered toA the toppedresiduum tank 40. Theoperation of coil I9 and column 22 is so regulatedas to produce the desired predetermined extent of topping necessary togive the proper viscosity oil in the later extraction of propane.

In the above description of the production of a topped residuum, theforegoing equipment and operations are intended merely to exemplify oneof the many ways iny which a satisfactory topped residuum can beprdduced. Many other features of construction and' operation such as areknown to those skilled in the art may be substituted for or included. inthe above without departing from my invention. It will be understoodthat the topping operation here described is equally applicable to theprocess illustrated in Figi 1.

The 'topped residuum from tank 40 is passed by pump 4| through line 42where it meets a propane solution of lubricating oil coming through line54. The propane and residuum pass through the turbulence or mixing coil43 and then into decanter 44. The asphalt in the residuum isprecipitated by the propane and settles to the bottom of decanter 44.The pre. cipitated asphalt resembles a slurry and may be drawn off fromthe bottom of the decanter with suiiicient liquid propane to permitpumping.

The asphalt propane slurry is passedl through line 45, pump 46 and line41 where it is mixed with fresh liquid propane from storage 48 sent viapump 49 and line 41. The mixture is then passed into mixing coil 50 andinto decanter 5|. If it is desired to produce an asphalt containingstill less oil or wax, the countercurrent washing with propane may beextended to as many steps as desired. Decanters 44 and 5| and storage 48are maintained at the same pressure by means of equilibrium lines 55controlled by valves 56. The pressures in 44, and 48 are suiiicient tomaintain the solvent in liquid state at ordinary temperatures.

The clear overflow from decanter 5| consisting of liquid propane inwhich is dissolved asmall amount of oil is sent through line 52, pump 53and line 54 to its connection with line 42 where it is mixed with theincoming topped residuum. 'Ihe mixed residuum and propane pass throughmixing coil 43 and into decanter 44 as described above.

The asphalt slurry from decanter 5| is drawn off through line |28 andpressure release valve |29 and is sent through line |30 to heating coil|3| set in furnace |32. In coil |3.| suiicient heat is supplied to causethe vaporization of the propane and to melt the asphalt.- The heatedmixture of asphalt and propane is now sent into evaporator |33 wheresuperheated steam is introduced via |34 in order to complete theevapora-- orator |33 is sent through line |35 to a cooler |36 which maybe a heat exchanger or simple cooler or a combination of both. Theproducts from the cooler |36 consisting of condensed steam and oiltogether with uncondensed propane are sent to separator |31. Thecondensed light oils are removed through |40 and the condensed Waterleaves through |4I. The uncondensed propane is carried by line |38 topressure regulating valve |39 and line |06 to the propane compressor|26. The compressed gas leaving compressor |28 travels through .line |06to cooler |21 where it liquefes and flows to liquid propane storage tank48. The pressure in |33 is about atmospheric.

The clear overow from decanter 44, now conthe pressure is released tothat corresponding tomatic pressure regulating valves. A tempera- .tureof about 40 F. is desirable in the followingl `valve 6|. The propanewhich has been vaporized in 58, in order to lower the temperature ot theremaining oilsolution, passes through line 68, valve 6| and line |86 tocompressor |26 where the .propane vapors are compressed; liquefied'andsent to propane storage 48 after cooling in cooler |21. i.

The cooled propane solution in expansion chamber 59 is sent through.line 62 by pump 68 to turbulence or mixing coil 61 and thence todecanter 68. Suliuric acid is introduced from .tank 65 by means of 4pump66 into line 64. 'Ihe acid treated oil solution is decanted `and thesludge isWithdrawn through line 68.` The oil is sent by line 18 and pump12| into turbulence or mixing coil 11 and thence to decanter 18. Water lfor use in washing the acid `treated oil is introduced in line 18from'water storage 12 via pump 13, valve 14 and line 16. The washed oilis then decanted and is removed from decan-ter 18 via line 88 and pump8| intoline 82. The Wash water is removed from decanter 18 through line18.

Alkali froml alkali storage 83 is then admitted to line 82 'via' pump 84and line 85. The oil and alkali flow through turbulencecoil 86 intodecanter 81 from which the alkali sludge is removed via line 88. Thedecanted oil from 81 The treated oil solution leaving the treating groupby means of line 8 5 is passedby pump 86 through a second expansionvalve 81 where to the dewaxing temperature. This pressure will besubstantially atmospheric and its correspond- `ing temperature will beabout 35 F. In order -to obtain an voil of extremely lowcold testand toreduce the danger of loss oi propane in the centrifuging operation,practically all of the propane is now evaporated. In order to maintainsuilicient fluidity and a proper specific gravity of the solution to bedewaxed by centrifuging, naphtha from tank 88 is added to the propanesolution in line 85 via pump 88 and line |88. The mixture of oil,propane and naphtha passes into expansion chamber l8|. of the propanereduces the .temperature of the remaining material to a satisfactorydewaxing temperature. The chilled material then passes through line |81to centrifuge |88 where the y wax is thrown out and carried away by line||8. 'I'he centrifuge is driven by motor |88. The wax stream may thenbetreated in any desired manner for thevrecovery of `naphtha andpropane. 'I'he dewaxed oil solution is lcarried away by line topump|'|2. From pump ||2 the oil 'Ihe evaporation` where the temperature israised by heat exchange with the bottoms from evaporator I I6 and column22 respectively, before being sent by lines ||4 and ||5 to evaporator||6. Evaporator ||6 may consist of any suitable equipment, but is shownas a simple column heated by steam coil In this exhausting column, allof the naphtha and any remaining propane are removed so that the oilremaining has proper flash and fire points. ,The overhead fromevaporator |6 passes through line '||1 to condenser ||8 and then toseparator I8. The naphtha recovered in` 8 is sent through line |22 tonaphtha storage 88V, andthe uncondensed propane is sent through line |28to back pressure regulating valve |2| and thence through line |86 to thepropane compressor |26 and liqueiler |21 to be returned to propanestorage 48. 'I'he bottoms from evaporator ||6 are drawn oil through line|23 and are sent to heat exchanger ||3 where heat' is imparted to theincoming Anaphtha solution as indicated above. Leaving heat exchangerH3, the bottoms pass through 4 line |24 to tank |25 which is the acidtreated dewaxed oil storage tank.

`It is to be understood that the above is merely illustrative ofpreferred embodiments ofthe invention of which many variations may bemade by those skilled in the art without departing from the spiritthereof.

I claim:

l. A method of separating asphalt ,and wax from oil containing the samewhich comprises mixing said oil with asolvent, separating the asphaltfrom the solvent, oil and wax, adding naphtha, separating thesolventfrom the naphtha, oil and wax at' reduced temperature, separatingthe wax from the oil and naphtha at reduced temperature and subsequentlyseparating the naphtha from the oil.

2. A method of separating asphalt and wax from oil containing the samelwhich comprises mixing said oil with asolvent, separating said asphaltfrom the solvent, oil and wax, removing part of said solvent before theaddition of naphtha, adding naphtha to said solventsolution, separatingthe remaining solvent from said solution, separating wax from the oiland naphtha and subsequently separating naphtha from the oil.

3. A method of separating asphalt and wax from oil containing 'the samewhich comprises mixing said oil with a volatile solvent undersuperatmospheric pressure sufficient to maintain said solvent liquid,separating said asphalt from the solvent, oil and wax under suchpressure, releasing the pressure to partially evaporate the solvent andto cool the oil .and precipitate the wax, adding naphtha, separating waxfrom said oil, naphtha and remaining solvent, further' mixing said oilwith a volatile solvent under superatmospheric pressure suiilcient tomaintain saidsolvent liquid, separating said asphalt from the solvent,oil and wax under such pressure, adding naphtha, reducing thetemperature and pressure, separating said solvent from the oil, wax

' and naphtha under reduced pressure, acid treating the oil and oil. u g

5. A process for the'production of lubricating Oil from an oilcontaining asphalt and wax which separating the naphtha from the andremaining propane from said acid treated oil.

comprises commingling said oil with liquid propane. separating theasphalt from the propane, oil and wax, adding a heavier solvent to saidpropane, oil and wax, cooling said oil, propane and heavier solventsuillciently to precipitate the wax, separating the precipitated waxfrom the oil, propane and heavier solvent and subsequently separatingsaid propane and said heavier solvent from said dewaxed oil.

6. A process for the production of lubricating oil from an oilcontaining asphalt and wax which comprises commingling said oil withliquid propane, separating the asphalt from the propane, oil and wax,adding naphtha to said propane, oil and wax, vaporizing a portion of theliquid propane and cooling the oil suiliciently to precipitate the Wax,separating the wax from the oil, naphthaA and remaining propane, acidtreating said oil in the presence of the naphtha and remaining propaneand subsequently separating the naphtha '7. A process for the productionof lubricating oil from oil containing wax which comprises mixing saidoil with a volatile solvent under superatmospheric pressure suillcientto maintain said solvent liquid, adding a wax extracting solvent,releasing the pressure and vaporizing4 the volatile solvent to cool theoil and precipitate the wax, separating the wax from the oil and waxextracting solvent and subsequently separating the wax extractingsolvent from the oil.

8. A process for the production of lubricating oil from oil containingwax which comprises mixing said oil with a volatile solvent undersuperatmospheric pressure sufllcient to maintain said solvent liquid,acid treating said oil and wax under said pressure in the presence ofsaid volatile solvent, alkali treating said acid treated oil and waxunder said pressure in the presence of said volatile solvent, addingnaphtha under said pressure, releasing the pressure and vaporizing thevolatile solventfrom the oil, wax and naphtha, separating the waxfromthe oil and naphtha ztiidlubsequently separating the naphtha from 9. Aprocess for the production of lubricating oil from oil containing waxwhich comprises mixing said oil with a liqueiied normally gaseoushydrocarbon solvent under superatmospheric pressure suilicient tomaintain said hydrocarbon solvent liquid, reducing the pressurepartially and vaporizing a portion',of the solvent to cool the oil, acidtreating said cooled oil in the presence of the remaining solvent,adding naphtha while maintaining the cooled oil solvent mixture undersaid reduced pressure. releasing the pressure and vaporizing the'solvent to further cool theoil and precipitate the wax, separating theprecipitated wax from the oil and naphtha and separating the naphthafrom the oil. i

i0. A process for the production of lubricating oil from oil containingwax which comprises mixins said oil with a liquefied normally gaseoushydrocarbon solvent and under superatmospheric pressure sufficient tomaintain said hydrocarbon solvent liquid, cooling the oil to atemperature insufiicient to precipitate substantial quantities of Wax bypartially reducing the pressure to effect vaporization of a portion ofthe solvent, acid treating said cooled oil in the presence of theremaining solvent under said partially reduced pressure, adding naphthaunder such pressure, releasing the pressure and vaporizing the 'solventto further cool the oil and precipitate the wax, separating theprecipitated wax from the oil and naphtha and subsequently separatingthe naphtha from the oil.

11. A. process for the production of lubricating oil from oil containingasphalt and wax which comprises mixing said oil with a liqueed normallygaseous hydrocarbon solvent under superatmospheric pressure sufficientto maintain said hydrocarbon solvent liquid to precipitate asphalt,separating the asphalt from the oil solvent solution, reducing thepressure partially and vaporizing a portion of the solvent to cool theoil, acid treating said cooled oil in the presence of the remainingsolvent, adding naphtha under such pressure, releasing the pressure andvaporizing the solvent to further cool, the oil and precipitate the wax,separating the precipitated wa'x from the oil and naphtha and separatingthe naphtha from the oil.

12. A process for the production of lubricating oil from oil containingasphalt and wax which comprises mixing said oil with a liquefiednormally gaseous hydrocarbon solvent under super.. atmospheric pressuresuiicient to maintain said hydrocarbon solvent liquid to precipitateasphalt, separating the asphalt from the oil solvent solution, coolingthe ,oil to a temperature insuiilcient to precipitate substantialquantities of wax by partially reducing the pressure to effectvaporization of a portion of the solvent, acid treating said cooled oilin the presence of the remaining solvent under said partially reducedpressure, adding naphtha under such pressure, releasing thepressure andvaporizing the solvent to further cool the oil and precipitate the wax,separating the precipitated wax vfrom the oil and naphtha andsubsequently separating the naphtha from the oil. 13. The process ofdewaxing hydrocarbon oils bearing a wax crystallization retarder in theform of coloring material, including the steps orf blending a diluentwith the hydrocarbon oil, chilling the solution thus formedsubstantially to a temperature at which' the retarding eilect of thecoloring material is overcome, removing such a portion of the coloringmaterial that the wax crystallization retardation eiect of the remainderwill not prevent substantially complete wax precipitation on furtherchilling, sub-chilling the solution to precipitate the wax andseparating the wax from' the solution. 4

14. A process according to claim 7 in which the volatile solvent is aliqueiled normally gaseous hydrocarbon having a vapor pressure higherthan that of butane and lower than that of ethane.

`15. A process according to claim 'l in which the volatile solventconsists chieily of liquid

